The present invention relates to a direct and selective production method for an iodine compound using iodine and a production process for high purity 5-iodo-2-methylbenzoic acid. Iodine compounds are important compounds, which are widely used as medicines such as contrast media and therapeutic agents for thyroid disease, sanitary materials for the purpose of anti-fungus and anti-mildew, electronic materials, optically functional materials, etching agents, catalysts and materials for chemical reactions in the fields of life science, electro-, info-communication, environment and energy. And high purity 5-iodo-2-methylbenzoic acid is a useful compound as a raw material for various performance chemicals in addition to medicines and agricultural chemicals.